Gas scrubbing apparatus has long been used for the removal of particulate material entrained in gas streams or for the absorption of noxious or otherwise selected gases and vapors from air or other gas streams. In the wet gas scrubbing process, a liquid, ordinarily water, is sprayed into the gas stream to wet and pick up the particulate matter after which the droplets holding the particulate material are removed from the stream and collected. It is well known that the efficiency of particulate removal is increased by passing the gas stream through a venturi tube with the scrubbing liquid sprayed into the stream just upstream of the throat. The rapid acceleration of the gases enhances the scrubbing action. The use of multiple-throat venturis offer special advantages in scrubber applications especially with respect to the efficient use of space.
An example of a multiple-throat venturi scrubber is shown and described in Ekman U.S. Pat. No. 3,488,039.
Conventionally, separators of the cyclone type are used to remove the particulate-laden scrubbing liquid downstream of the multiple-throat venturi scrubber. The vane-type separators, such as that shown in Halter et al U.S. Pat. No. 3,405,511, are also used to remove entrained liquid particles from gaseous streams.
Conventionally, although not invariably, scrubbing apparatus has been designed for upward flow of the gas stream through the scrubber components, the inlet being horizontal for connection with a horizontal run of duct. The scrubber outlet at the top of the unit may be horizontal or vertical.
Industrial scrubbing apparatus must be designed to meet the requirements of a particular application with particular reference to the volume and flow characteristics of the gas to be treated, the nature of the particulate or gaseous matter to be removed and other physical factors. With application specifications established, the scrubbing apparatus, usually very large, is largely custom designed, fabricated and shipped to the site. This approach is time consuming, and frequently involves very expensive damage in shipment.
The object of the invention is to provide in-line wet scrubbing apparatus composed of modular component parts and having horizontal, substantially coaxial inlet and outlet for convenient and space-efficient connection in a horizontal run of the gas-flow duct in the industrial plant. A further object is to minimize both the production time and cost of such scrubbing apparatus by standardizing multiple-throat venturi and vane-type demister subassembly sections whereby standard modular components may be fabricated in the factory and shipped for on-site fabrication of the scrubbing apparatus in position for use with minimum need for special parts and shapes. A further object is to provide scrubbing apparatus with successive demister components adapted for the successive removal of coarse and fine liquid particles.
The ultimate object of the invention is to provide wet scrubbing apparatus which can be supplied without undue delay, at greatly reduced cost and requiring minimum space on location.